Electrochemical storage devices used in EV must fulfill certain requirements, so that the EV can perform in a satisfactory manner. The key requirements are as follows:

• High specific energy to ensure a satisfactory range
• High specific power so that drivers acceleration expectations can be met
• Long, maintenance free lifetime
• Safe operation under a wide range of conditions
• End of life disposal has minimum environmental impact
• High efficiency in charge and discharge cycles.

The power and energy requirements for different types of EV’s in comparison with HEV and PHEV are listed in the Table below, together with common voltage ratings. For the purposes of this module five categories of EV batteries are described, which is similar to that described by Van den Bossche¹ and Westbrook². These categories are outlined as follows:

• Lead acid
• Nickel based: NiMH, NiCad
• High temperature: Sodium-nickel-chloride (NaNiCl or Zebra)
• Lithium based : Lithium-ion (Li-ion) and Lithium-polymer (Li-poly)
• Metal air: Aluminium air (Al-air) and Zinc-air (ZN-air)

Table: Typical EV Battery Electrical Parameters

EV type	Power (kW)	Energy (kWh)	Voltage(V)
HEV	20 – 50	1 – 3	200 – 350
PHEV	>40	2 – 15	200 – 500
BEV	>80	25 – 100	200 – 1000

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^{1. [Van den Bossche, P., et al., SUBAT: An assessment of sustainable battery technology. Journal of Power Sources, 2005. 162(2)]}

^{2. [Westbrook, M.H., The Electric Car: Development and future of battery, hybrid and fuel-cell cars. IEE Power Series no. 38. 2001]}